Conventional signal distribution systems include, by way of example, cable television systems, satellite television systems, and systems providing Internet protocol television (IPTV) over digital subscriber line (DSL) or fiber. Such systems are configured to distribute media streams associated with subscription television services to system subscribers or other users. Typically, a given subscriber is provided with an interface device, such as a set-top box or receiver, for communicating with system head end equipment. The interface device is configured to permit the subscriber to receive, on a television or other presentation device coupled to the interface device at a given location, the particular subscription television services to which that subscriber is entitled by virtue of the subscription. A given subscription may encompass, by way of example, a number of basic broadcast channels, as well as one or more premium programming channels, such as movie channels, sports channels, specialty channels, pay-per-view channels, on-demand video channels, etc.
A number of techniques are known for providing targeted advertisements in a signal distribution system of the type described above. One example is described in PCT International Publication No. WO 02/47384, entitled “Method and Apparatus for IP Multicast Content Distribution System Having National and Regional Demographically Targeted Advertisement Insertion.” In this technique, demographic targeting of inserted advertisement content is accomplished on a per-stream basis at a regional network level by modifying header information during a packet replication process.
A problem with these and other known techniques is that the advertisement insertion process is typically carried out entirely in head end equipment of the system, so as to be fully transparent to the interface device. Thus, the interface device at the user location is not even aware that the targeted insertion is taking place, and cannot distinguish between a stream having inserted targeted advertisements and an ordinary stream. This type of arrangement unduly limits the flexibility of the system, and may prevent it from achieving a desired level of granularity in its targeting of advertisements to particular groups of users. It also makes it difficult to adapt the insertion process to situations such as a user changing a channel while a targeted advertisement is being played.
Accordingly, a need exists for improved techniques for targeted advertisement insertion in cable, satellite and IPTV systems, as well as other types of signal distribution systems.